Electjeiode



I. S. CROCKER.

ELECTRODE.

APPLICATION FILED MAR. 11, 1921.

1 06,542 Patented. Feb. 14, 1922.,

Inventor Irving S. Crockerf,

His Attorney @FFEQE.

I IRVING- S. CRIOCKER, F LYNN, MASSACHUSETTS, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRODE.

Application filed March 17, 1921.

T 0 all whom' it may concern:

Be it known that I, IRVING S. QRooKER, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Electrodes, of which the following is a specification.

My invention has reference to an improved process of making electrodes having the electrode material strongly compressed in a shell of metal. Electrodes of this general character are known in the art and among the electrodes thus constructed are principally those in which the electrode material is composed largely of magnetite with some additions of titanium oxide of fluxes. These electrodes are known as magnetite electrodes.

Originally such electrodes were made by simply filling the ground ,magnetite material into an iron shell which was closed at one end and then bumping the electrode whereby the material became moderately compacted within the shell; after this, the open end of the shell was closed by a cap. It was found thatin this manner the density of the electrode as a whole was rather low. and the electrodes were consumed at a comparatively high rate. Thiswas afterwards overcome by proceeding as hereinbefore indicated and then swaging the electrode or drawing the same through dies of ever decreasing diameters. whereby the electrode material was greatly compacted until it became practically as hard as a rock. In this manner more electrode material. was condensed in electrodes of the same diameter and length than was possible by the simple bumping process. But the defect of this improved process was that by the sw'aging or drawing process the resulting electrode was generally longer than required or permitted in commercial arc-lamps, and these superfluous extensions had to be cut off and the material which they contained was in a large measure lost. In addition thereto, by the swaging or drawing process, the shell became verythin, and thus detracted from the conductivity of the electrode as a whole.

My invention is designed to.and does overcome the defects of the old process of swaging or drawing, by so compressing the bumped electrode to a smaller cross-section that its length is not altered and the shell or casing is not reduced in thickness. In

Specification of Letters Patent. Patented Feb. 14,

Serial No. 452,904.

I this manner, none of the original electrode one of the electrodes finished and two others in course of undergoing the process; and Fig. 4 is a perspective view of thefinished product.

Referring to the drawing, the cylindrica-l shell 10 of the electrode blank is shown in Fig. 1 as filled with the electrode material 11, which is moderately compacted therein by bumping. One end of theshell is reduced in diameter as indicated at 12 by any desired process, and this neck of the electrode which is designed to be received in a holder in the lamp, is closed by a. thimble 13 before the electrode material is filled in, andthe wide open end of the shell is then closed by a cap 14. The electrode, so far described, is of the old type and which for the purposes of my invention is used as a blank.

.The press used inmy process consists of a heavy base 15 and a follower 16, the base being formed with a mold cavity 17 which has the length of the blank, but is provided at each end with a limit stop (not indicated in the drawing) so that the open cavity in the base block has just the length of the electrode blank, whereby the latter, in the subsequent step of the process, can only be compressed in cross section, but cannot be elongated. The die channel or mold cavity is here shown rectangular in form, and it is narrower than the diameter of the electrode blank, so that the latter, in its original cylindrical form, could not be entered into the die cavity. With this equipment, the improved process is as follows:

Upon the upper surface of the base block are placed two electrode blanks in their original cylindrical form, as indicated in Fig. 2, and the follower is then forced down until its side branches 16 press upon the blanks and partly flatten them, as indicated in Fig. 3. Vhen the process is thus primarily started the die cavity would ordinarily be empty, since the diameter of the cylindrical blank is too large to be placed in the cavity. 'After one or more flattened blanks have thus been made, one of them is placed in the mold and two cylindrical blanks are put in place as shown in Fig. 2. If now the follower is forced down, as shown in Fig. 3, the flattened blank in the mold is powerfully compressed to a smaller cross-section and is given the shape of the mold without'lengthening the electrode. the same time two of the original cylindrical blanks are flattened, so that they or one of them may be inserted in the mold to be acted upon by the follower at its next stroke. The final form of the electrode is shown in Fig. 4. It is rectangular in cross-section and may be square. It is, however, clear that the final cross-section of the electrode may be different; it may be polygonal or have any desired form if the mold cavity and the follower are suitably formed. The finished electrode is discharged from the mold in any suitable manner as, for instance, by one or more, expelling rods 18, indicated in Figs. 2 and 3.

What I claim, as new and desire to secure by Letters Patent of the United States is 1. The process of making a dense arclight electrode'which consists in filling a metallic shell with the powder of the electrode material and then compressing the filled shell to a smaller cross-section without elongating the same 2-. The process of making a dense arclight electrode which consists in filling a substantially cylindrical metallic shell with powdered electrode material and then compressing the filled shell to a smaller, angular cross-section without elongating the same.

in witness whereof, I have hereunto set my hand this 14th day of March, 1921.

IRVING S. CROCKER. 

